feat(agent): complete EvoAgent integration for all 6 agent roles

Migrate all agent roles from Legacy to EvoAgent architecture:
- fundamentals_analyst, technical_analyst, sentiment_analyst, valuation_analyst
- risk_manager, portfolio_manager

Key changes:
- EvoAgent now supports Portfolio Manager compatibility methods (_make_decision,
  get_decisions, get_portfolio_state, load_portfolio_state, update_portfolio)
- Add UnifiedAgentFactory for centralized agent creation
- ToolGuard with batch approval API and WebSocket broadcast
- Legacy agents marked deprecated (AnalystAgent, RiskAgent, PMAgent)
- Remove backend/agents/compat.py migration shim
- Add run_id alongside workspace_id for semantic clarity
- Complete integration test coverage (13 tests)
- All smoke tests passing for 6 agent roles

Constraint: Must maintain backward compatibility with existing run configs
Constraint: Memory support must work with EvoAgent (no fallback to Legacy)
Rejected: Separate PM implementation for EvoAgent | unified approach cleaner
Confidence: high
Scope-risk: broad
Directive: EVO_AGENT_IDS env var still respected but defaults to all roles
Not-tested: Kubernetes sandbox mode for skill execution

backend/agents/workspace_manager.py

@@ -1,5 +1,5 @@
 # -*- coding: utf-8 -*-
-"""Initialize run-scoped agent workspace assets."""
+"""Initialize run-scoped agent workspace assets under `runs/<run_id>/`."""
 
 from pathlib import Path
 from typing import Dict, Iterable, Optional
@@ -479,5 +479,6 @@ class RunWorkspaceManager:
         )
 
 
-# Backward-compatible alias: code importing WorkspaceManager from this module should continue to work.
+# Backward-compatible alias: many runtime paths still import WorkspaceManager
+# from this module when they mean the run-scoped manager.
 WorkspaceManager = RunWorkspaceManager